Küstenmeer

Küstenmeer is the term used in German for a state's territorial sea, the belt of coastal waters extending from the baseline to a defined offshore distance. It forms part of the coastal state’s sovereignty, including jurisdiction over the water column, seabed and airspace above, while foreign vessels retain certain rights, notably the right of innocent passage.

The baseline from which the distance is measured is usually the low-water line along the coast, though straight baselines may be permitted under international law. The territorial sea typically extends up to 12 nautical miles from the baseline. The concept and its rules are established by the United Nations Convention on the Law of the Sea (UNCLOS) and implemented in national legislation, such as Germany’s Seerecht.

Within the Küstenmeer, the coastal state exercises sovereign rights and jurisdiction, subject to international law. This includes enforcement of laws related to navigation, safety, pollution prevention, and resource management. Foreign ships may sail through the territorial sea under the principle of innocent passage, provided their passage is continuous and not prejudicial to the peace, security, or order of the coastal state.

Beyond the Küstenmeer lie other maritime zones with different rights, such as the contiguous zone, the exclusive economic zone, and the high seas. Internal waters lie landward of the baselines and are not part of the Küstenmeer; they are considered part of the state’s inland waters. The concept of Küstenmeer thus anchors a core element of maritime sovereignty in international and national law.